Throughout this specification including the claims, the term “rotary machine” is intended to include both motors and pumps that act or operate on, or, are driven or otherwise operated by, a fluid.
Rotary machines have been known and used in various industries ever since the industrial revolution. In general terms, when operated as a motor, a high pressure fluid is fed through the machine and the pressure of the fluid used to impart motion to mechanical components to generate a mechanical kinetic energy used to power or drive some other machine. When operated as a pump, mechanical power is imparted to moving components of the pump which displace or force fluid through the machine to create a fluid flow and thus a pumping action.
The Applicant has been particularly innovative in the design and manufacture of rotary machines including, although not limited to, rotary machine for use as motors in oil and gas directional drilling. An example of such a rotary machine, configured as a motor is described in International Application No PCT/AU97/00682. A substantial benefit of the motor described in the aforementioned application is that, in comparison with other known motors, it has a substantially higher power density or power to weight ratio. This enables the motor to be of a significantly shorter length for the same power output as a conventional motor. This allows greater precision in directional control of a directional drill and the ability to turn at substantially smaller radii that can be achieved with the prior art.
Notwithstanding the substantial benefits of the motor described in the aforementioned application, the Applicant continues to conduct research and development in the area of rotary machine design. This research and development has led to the invention described herein.